There is a detailed workflow to calculate the Climate Indicators (CI) provided in the Climate Information Portal. Many quality controls are completed throughout the production workflow to ensure that the indicators are of high quality.
The chart in the figure below describes the different steps in the workflow and highlights (in orange) the quality control procedures. Each procedure is adapted to the dataset it is applied to (to account for different variables, ranges and more), and can be repeated throughout the workflow. Essential Climate Variables (ECV) from Global Climate Models (GCM) are downloaded from the Earth System Grid Federation (ESGF), the largest archive of climate data world-wide. ESGF has already some standards which the climate community follows in order for the output of the climate models to be available to the scientific community.
Types of quality control procedures
File format checks/pre- and post-processing
- Data gaps/overlapping periods or missing values. The check ensures that the data is without gaps and does not have overlapping periods or missing values. Cases when a part of the time series was missing (e.g. a missing 5-year time-slice file) led to exclusion of the projection from the ensemble.
- Units appropriate for each indicator; e.g. the climate model temperature unit is in general Kelvin (K), and values are then converted to Celsius (ºC).
- Data dimensions: Check that all data comes on the same grid and has the same number of time steps.
- Time calendar definition: Check that all data has been converted to the same calendar.
- The metadata relevant to the CI production is checked to be complete, correct and follow the metadata standards. All files are edited to make metadata homogeneous.
- Converting calendar to standard time reference
- For bias-adjusted data: remapping data to HydroGFD3.2 grid with 0.25 degrees spatial resolution
- For non-adjusted data: remapping data to a grid with 2.0 degrees spatial resolution
Range check on Essential Climate Variable (ECV) data
Evaluation of bias adjustment
Evaluation of climate indicators
Quality checks for climate impact indicators, both non-adjusted and bias-adjusted CI are done in steps 5 and 6 in figure.
- Metadata and filenames are checked to follow the pre-defined CI-specifications.
- Unreliable data is masked out, e.g. in regions where relative changes of precipitation become unreliably large due to very low values in the reference period.
- CI data is evaluated against CIs derived from reference data and compared to all other projections. If any projection shows large deviations, the data is inspected in more detail by experts.